Hinge for sewing machines



Sept. 9, 1969 D. LAWRIE ET AL HINGE FOR SEWING MACHINES Filed Feb. 28, 1967 Fig. 2

INVENTORS" Donqid Lawg'ie and BYCampbeH FmJloy WITNESS ATgORNEY United States Patent 3,465,381 HINGE FOR SEWING MACHINES Donald Lawrie, 'Clydebank, and Campbell Findlay,

Glasgow, Scotland, assignors to The Singer Company, New York, N .Y., a corporation of New Jersey Filed Feb. 28, 1967, Ser. No. 619,359 Claims priority, application Great Britain, Nov. 10, 1966, 50,351/ 66 Int. Cl. Ed 11/08, 11/10 U.S. Cl. 16-142 5 Claims ABSTRACT OF THE DISCLOSURE A hinge for the cover plate of a sewing machine frame comprising a bracket mounted on the frame for pivotally supporting the cover plate and a spring mounted with the bracket and disposed relative to pressure receiving means on the cover plate such that the spring will maintain the cover plate either in its opened or closed position.

The present invention relates in general to sewing machines, aud in particular to an improved hinge therefor, such hinge serving to support pivotally, for example, a replaceable cam cover plate in either of two rest positions.

Prior art hinges over which the invention improves are, for example, those shown in FIGS. 3 and 5 respectively of US. Patents Nos. 2,848,963 and 3,027,857, both assigned to the instant assignee. The principal characteristic of each of these prior art hinges is the employment of flat cantilever springs to urge unidirectionally pivotal shaped bosses on a sewing machine cam cover plate toward and into notches formed in the sewing machine bracket arm lid, the shape of the bosses being definitive of the open and closed conditions of the cam cover plate. With each such hinge the sewing machine bracket arm is further provided with spring accommodating openings in the rear side of the bracket arm, wherein the spring ends reside. The hinge of the invention has no requirement that bosses be specially shaped, nor does the invention require that the sewing machine bracket arm lid be formed with boss accommodating notches, or that the bracket arm have rear side openings. Aside from being thereby less costly to manufacture, and obviously esthetically superior, the hinge of the invention has also proved less susceptible to inadvertent disassembly, this being because the bosses thereof serve solely as spring pressure points, with the cam cover plate, as will be described later, being securely pivotal on a journal rigidly supported by the bracket arm lid.

The principal object of the invention is to provide improved hinge apparatus for sewing machines that facilitates manufacturing thereof and esthetically improves over known prior art sewing machine hinges.

The invention will be described with reference to the figures, wherein:

FIG. 1 is a side elevational view, partially in section, of a sewing machine bracket arm assembly embodying a hinge according to the invention, and showing the cam cover plate thereof in its closed position,

FIG. 2 is a view like that of FIG. 1, but showing the sewing machine cam cover plate in its opened position,

FIG. 3 is a perspective view illustrating the hinge of the invention, and

FIG. 4 is an exploded view useful in describing the assembly of the hinge of FIGS. 1-3.

Referring to the figures, the bracket arm of a sewing machine supports in the hollow thereof a rotary cam 12 for effecting the sidewise throw of the sewing machine needle, whereby zigzag and other fancy stitches may be effected. The cam 12 is detachably supported by a drive Patented Sept. 9, 1969 shaft 14 that is driven in timed relation to the sewing machine needle. The bracket arm 10 is provided with a lid 16 having therein a receptacle opening 18 for exposing the cam-supporting end of the shaft 14. The receptacle opening 18 is adapted to be covered by a cam cover plate 20 that is hinged to the bracket arm lid 16; and it is this hinging which is the subject of the invention.

The underside of the cam cover plate 20 is provided with a flange 22 serving as a lever, the fulcrum of which is provided by a journal 24. The flange 22 has a cutout 23 designed for straddling the rear wall of the bracket arm 10; and the journal 24 is supported by a hinge bracket 26 that is secured by means of screws 28 to the underside of the lid 20. The bracket 26 has two arms 26a, 26b joined by a cross piece 260, and it is this cross piece, in particular, that is secured to the lid 16. The lid 16 has an opening 25' through which the flange 22 extends, and which opening is unobservable when the cover plate 20 is closed.

The flange 22 is provided with bosses 30 disposed a distance from the pivotal journal 24, against which bosses 30 cantilever springs 32a, 32b are adapted to bear. The springs 32a, 32b form part of a spring bracket 32 adapted to be secured to the lid 16, between the lid and the bracket 26, by means of the screws 28; and the bosses 30 constitute the ends of a pin 34 situated within the flange 22.

The location of the bosses 30 relative to the pivotal axis of the cover plate flange 22 is critically such that the springs 32a, 32b are biased downwardly against the bosses 30, whether the cover plate 20 is in its opened or closed position. For example, with the cam cover plate 20 closed as depicted in FIG. 1, the springs 32a, 32b bear downwardly against the bosses 30 which locate approximately midway between the ends of their respective springs. This exerts a counterclockwise torque (looking at FIG. 1) on the flange 22 to hold the cover plate 20 closed. By lifting the cover plate 20, the flange 22 pivots on its journal 24 and in so doing causes the bosses 30 to ride upwardly and outwardly toward the ends of the springs 32a, 32b thereby increasing the tension of the springs. As the bosses 30 pass their top-dead-center relationships with respect to the pivotal journal 24, the torque applied to the flange 22 shifts to one that is clockwise (looking at FIG. 2), whereby the cover plate is held open. The bends 40a, 40b in the springs 32a, 32b serve to prevent the springs from slipping off their respective bosses when the cover plate 20 is opened fully.

As can be appreciated from FIG. 3, the hinge of the invention itself prevents exposure of the mechanisms within the hollow of the bracket arm 10' when the cover plate 20 is opened; and as can be appreciated from FIG. 1, such bracket arm mechanisms are not exposed through holes or the like in the rear of the bracket arm 10 when the cover plate is closed. This adds to the attractiveness of the sewing machine in question, and as will be apparent leads to greater utility of the invention.

While the invention has been described in its preferred form, it is to be understood that the words which have been used are words of description rather than of limitation, and that changes within the purview of the appended claims may be made without departing from the true scope and spirit of the invention. For example, it would be well within the scope of the invention to use only one spring (32a or 32b) for biasing purposes since the pivotal point for the cover plate 20 is defined solely by the journal 24. Also, it would be well within the scope of the invention to put a generally longitudinal slice in the flange 22, and to bring say a single spring to bear against the middle of the pin 34. So too, while flat cantilever springs are preferred, other for-ms of cantilever springs may be employed for biasing the cover plate opened or closed.

Having thus set forth the nature of this invention, what is claimed herein is:

1. Hinge apparatus for the cover plate of a sewing machine frame, comprising flange means on said cover plate, a boss member formed on said frame, bracket means on said frame for pivotally supporting said flange means, pressure receiving means on said flange means, and spring means for applying pressure to said pressure receiving means, said spring means having at least one abutment at one extremity thereof for preventing said spring means from slipping off said pressure receiving means when said cover plate is opened, means for securing said bracket means and said springs means to said boss, said pressure receiving means and said spring means being so disposed with respect to each other and to the pivotal point of said flange means that said spring means applies opening and closing torques to said flange means depending respectively on whether said cover plate is in its opened or closed position.

2. The apparatus of claim 1 wherein said pressure receiving means is a boss on said flange means, and wherein said spring means is a cantilever spring.

3. The apparatus of claim 1 wherein said flange means has a cutout portion adapted for straddling a wall of the sewing machine frame when said cover plate is in its opened condition, and wherein said frame is provided with an opening through which said flange means is adapted to extend.

4. Hinge apparatus for the cover plate of a sewing machine frame, comprising flange means on said cover plate, bracket means including a pair of spaced apart arms and a journal being disposed on said frame for pivotally supporting said flange means between said arms, pressure receiving means comprising a pair of bosses on said flange means, and spring means comprising a pair of cantilever springs aligned and biased to bear against said bosses, said pressure receiving means and said spring means being so disposed with respect to each other and to the pivotal point of said flange means that said spring means applies opening and closing torques to said flange means depending respectively on whether said cover plate is in its opened or closed condition.

5. The apparatus of claim 4 wherein said flange means has a cutout portion adapted for straddling a wall of the sewing machine frame when said cover plate is in its opened condition, and wherein said frame is provided with an opening through which said flange means is adapted to extend.

References Cited UNITED STATES PATENTS 1,165,894 12/1915 Negraval l6142 1,690,552 11/1928 Reutter 22035 1,332,202 3/ 1920 Cole 220-35 BOBBY R. GAY, Primary Examiner D. L. TROUTMAN, Assistant Examiner US. Cl. X.R. 16--l45 

